Implantable electrical stimulators have been proposed for use to treat a variety of symptoms or conditions, such as chronic pain, tremor, Parkinson's disease, epilepsy, urinary or fecal incontinence, sexual dysfunction, obesity, or gastroparesis. An electrical stimulator may be configured to deliver electrical stimulation therapy to a patient via one or more medical leads that include electrodes implanted proximate to a target tissue within the patient, such as a target tissue site proximate the spinal cord, pelvic nerves, peripheral nerves, or within the brain or stomach of a patient. Hence, electrical stimulation may be used in different therapeutic applications, such as deep brain stimulation (DBS), spinal cord stimulation (SCS), pelvic stimulation, gastric stimulation, or peripheral nerve stimulation. Stimulation also may be used for muscle stimulation, e.g., functional electrical stimulation (FES) to promote muscle movement or prevent atrophy.
Electrical stimulation may be delivered via one or more implanted or percutaneous leads, each lead carrying one or more electrodes. The electrodes may take the form of, e.g., ring electrodes, cuff electrodes, paddle electrodes, segmented ring electrodes. Leads may be constructed, for example, by welding each electrode to a conductor (e.g., a wire) disposed within a lead body of the lead. When completed, an electrical signal generated by the electrical stimulator may be transmitted through one or more conductors and respective electrodes of the lead to generate an electrical field within the patient.